Microplate lid

ABSTRACT

A microplate lid having a substantially flat, generally rectangular top with first and second pairs of opposite sides. A flange depends from the top of the first and second pairs of sides, the flange bearing at least one recess area along each side of the first pair of sides, the recessed area extending into the top.

The present application claims the benefit of the filing date of thefollowing applications: U.S. patent application Ser. No. 09,030,578,filed Feb. 24, 1998, now pending; U.S. patent application Ser. No.09,028,283, filed Feb. 24, 1998, now pending: each of which areincorporated herein by reference.

BACKGROUND

This invention relates to the field of biomedical testing, and moreparticularly to the transport, handling and processing of biomedicalsample holders such as microplates. Microtiter plates, commonly known as“microplates” facilitate the simultaneous testing (or other processing)of a large number of individual biomedical samples. Microplates havebeen in common use for decades with a predominant format being a moldedplastic plate having 96 sample wells in an 8×12 rectangular array.Typical well volumes are 200 or 300 microliters depending upon themanufacturer and model of plate, although other volumes may be providedfor specific uses. A proposed standard, designated “Microplate 96-WellStandard” (MP96) has been promulgated by The Society for BiomolecularScreening, as published in Journal of Biomolecular Screening, Volume 1,Number 4, 1996, the disclosure of which is incorporated herein byreference. A microplate which meets the general dimensional requirementsof the standard is designated MP96-3. Typically, each microplatemanufacturer will also provide a compatible lid. A typical lid comprisesa generally rectangular flat planar top surrounded by a flange dependingfrom the top along its sides and edges.

Automated handling of microplates has become an important criterion intheir design. It is therefore desirable to provide a microplate lidconfiguration that facilitates use with automation. Specifically, it isdesirable to provide a lid that facilitates automatic stacking andunstacking of lidded microplates, automatic stacking and unstacking oflids without microplates, and automated installation and removal of lidsfrom microplates.

SUMMARY

In one embodiment, the invention is directed to a lid which is theunitarily formed combination of a substantially flat, generallyrectangular top having first and second pairs of opposite sides and aflange, depending from the top along the first and second pairs ofsides, the flange bearing at least one recessed area along each of thefirst pair of sides, the recessed area extending into the top.

Some implementations may include one or more of the following: (1) eachside of the first pair of sides may have two such recessed areas; (2)each side of the second pair of sides may have at least one recessedarea extending toward the top; (3) each side of the second pair of sidesmay have one recessed area extending toward but not reaching the top.

In one embodiment, the flange may bear two recessed areas along each ofthe first pair of sides extending into the top and two recessed areasalong each of the second pair of sides extending into the top, with athird recessed area along each of the second pair of sides, between thetwo recessed areas that extend into the top on such sides, but notreaching the top. The three recessed areas of each of the second pair ofsides may be contiguous and the third recessed area may have asubstantially straight leading edge. The lid may have a sealing featurefor sealing to the top of the microplate and the sealing feature maycomprise a substantially continuous lip depending from the lower surfaceof the top slightly inboard of the sides and uninterrupted by any of therecesses.

A further embodiment of the invention is directed to a process foradding to and removing from a stack of lidded microplates. The initiallowermost microplate in the stack is supported at a first height by apair of opposite, inwardly-directed support features of astacking/unstacking machine, each remaining microplate in the stackresting atop the lid of the microplate immediately below. The processmay include the steps of adding an additional microplate to the stack asa new lowermost microplate by elevating the additional microplate withan elevator from below the stack until the lid supports the initiallowermost microplate, the support features bring accommodated by a pairof opposite, inwardly-directed recesses in the lid of the additionalmicroplate. The support features are separated to allow passage of theadditional microplate and the additional microplate is further elevateduntil it reaches at least the first height, whereupon the supportfeatures may be inserted beneath the additional microplate and theelevator lowered so as to disengage the elevator from the stack, leavingthe stack supported by the support features and leaving the additionalmicroplate as the new lowermost in the stack. The process may berepeated with further microplates added to the stack in place of the newlowermost microplate.

The invention may further provide for the removal of a microplate fromthe stack by raising an elevator to engage the lowermost microplate,further raising the elevator to disengage the stack from the supportfeatures, separating the support features and lowering the elevator. Thesupport features may be reinserted so that they are accommodated by apair of opposite, inwardly-directed recesses in the lid of the lowermostmicroplate and the elevator further lowered so that the microplate abovethe lowermost microplate is engaged by the support features and becomesthe new lowermost microplate as the previous lowermost microplate may beremoved.

In a further embodiment, the invention provides for removing amicroplate lid by introducing a pair of stop features to a pair ofopposite, inwardly-directed recesses in the lid of the microplate so atleast a portion of the stop features are positioned directly over atleast a portion for the microplate. The lid may be raised with the stopmembers preventing movement of the microplate so as to permit separationof the lid from the microplate. The raising of the lid may compriseintroducing a pair of lifting features into a pair of opposite,inwardly-directed recesses in the lid with at least a portion of thelifting features extending immediately below a portion of the lid.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a lid according to principles of theinvention.

FIG. 2 is a top view of the lid of FIG. 1.

FIG. 3 is an end view of the lid of FIG. 2.

FIG. 4 is a side view of the lid of FIG. 2.

FIG. 5 is a partial cross-sectional view of the lid of FIG. 2, takenalong line 5-5.

FIG. 6 is a semi-schematic view of a system for stacking and unstackinglidded microplates according to principles of the invention.

FIGS. 7-10 are semi-schematic views of the stacking system of FIG. 6 invarious stages of operation.

FIGS. 11 & 12 are partial-schematic views of a system for removing lidsfrom microplates according to principles of the invention.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

One embodiment of a microplate lid according to principles of theinvention is shown in FIG. 1. The materials for manufacturing the lidwill typically be polymeric, since these materials lend themselves tomass manufacturing techniques, for example polystyrene or a cycloolefinpolymer. However, other materials can be used such as glass or quartz.Preferably, polymers are selected that have low fluorescence and orreflectance. Additionally materials such as polymers can includepigments to darken the lid and absorb light. Such application ofpigments will help reduce background fluorescence. Pigments can beintroduced by any means known in the art, such as coating or mixingduring the manufacture of the material or multi-well platform. Pigmentselection can be based on a mixture of pigments to dampen all backgroundinherent to the polymer, or a single pigment or ensemble of pigmentsselected to filter or absorb light at desired wavelengths. The lid 20comprises a generally rectangular top 22 preferably having planar upperand lower surfaces 24 FIGS. 2 and 26, respectively. A flange 30 dependsfrom all four sides of the top. For purposes of exposition, the shortersides are referred to as a pair of front and back ends 32 a and 32 b,and the longer sides as left and right sides 34 a and 34 b,respectively. With the exception of the presence of recesses (describedbelow), the flange 30 continuously surrounds the top in the preferredembodiment.

On opposite sides of a transverse centerline 102, the flange bears arecessed area 42 a and 42 b and 44 a and 44 b along each side 34 a and34 b, respectively, extending toward and slightly into the top.Similarly, on opposite sides of the longitudinal centerline 104, theflange bears a recessed area 46 a and 46 b and 48 a and 48 b along eachend 32 a and 32 b, respectively, extending toward and slightly into thetop. Along each end 32 a and 32 b, the flange also bears a slightlyrecessed area 50 a and 50 b, respectively, positioned centrally betweenand connecting recessed areas 46 a and 48 a and 46 b and 48 b,respectively FIG. 3. Although recesses 50 a and 50 b extend slightlytoward the tops they do not reach it, having straight leading edges 52 aand 52 b which are recessed only slightly relative to the leading edge31 of the remainder of the flange.

In the exemplary embodiment, the general dimensions of the top areapproximately 5.03 inches in length between the ends, and 3.25 inches inwidth between the sides, with a thickness of 0.06 inches. The flange 30has a depth (D1) of 0.25 inches (from the upper surface of the top tothe leading edge 31 of the flange) and the central recessed areas 50 aand 50 b are recessed by a distance D2 of 0.125 inches from the leadingedge 31 of the flange.

As shown in FIG. 5, a sealing feature 56 depends from the lower surfaceor underside 26 of the top 24 and is formed as a substantiallycontinuous lip, located slightly inboard of ends 32 a and 32 b and sides34 a and 34 b and uninterrupted by the recesses. The sealing feature cansupport the lower surface 26 of the top above the upper surface or topof the microplate and may provide a seal with the microplate. In theexemplary embodiment, the sealing lip extends 0.03 inches below theunderside 26 of the top 24.

Shown in FIG. 6 is an apparatus for stacking and destacking liddedmicroplates. The apparatus includes an elevator comprising four threadedlifting shafts 202. Rotation of the shafts will raise or lower theshafts relative to a base 204 so that their upper ends 206 can engagethe bottom of a microplate. As further shown in FIG. 7, in an exemplaryprocess for adding to and removing from a stack 210 of liddedmicroplates, an initial lowermost first microplate 214 is supported at afirst height HI by a pair of opposite, inwardly-directed, supportfingers 212. Each remaining microplate in the stack rests atop the lidof the microplate immediately below. As shown in FIGS. 7 and 8, a secondlidded microplate 216 (FIG. 8) is brought under the stack such as bymeans of a conveyor belt 218 around which the shafts 202 are free topass. The shafts are rotated so that they raise and engage the bottom ofthe second microplate 216. Further rotation elevates the microplateuntil its lid supports the first microplate 214, the support fingersbeing accommodated by the recesses 42 a and 42 b and 44 a and 44 b (FIG.9). The support fingers are then separated to allow passage of thesecond microplate 216 and the second microplate is further elevateduntil it reaches a height H2 slightly above height H1 FIG. 10. Thesupport fingers are then reinserted beneath the second microplate andthe shafts counter-rotated to descend, and leave the stacks 210supported at height H1 with the second microplate 216 as the newlowermost microplate. The shafts may then be further lowered to theiroriginal position to receive a third microplate and the procedurerepeated to make the third microplate a new lowermost microplate in thestack.

The procedure may be substantially reversed to remove the lowermostmicroplate from the stack. To do this, the shafts are raised until theyengage the lowermost microplate 216 at height H1 and then further raisedto height H2 to disengage the stack from the support fingers 212 FIG.10. The support fingers are then separated, allowing the stack to belowered until the support fingers can be reinserted so that they areaccommodated by the recesses in the lid of the lowermost microplate 216FIG. 9. The shafts may be further lowered so that the support fingersengage the microplate 214 immediately above the lowermost microplate216, microplate 214 then becoming the current lowermost microplate inthe stack. The previous lowermost microplate 216 is then lowered furtherand may be removed.

As shown in FIGS. 11 & 12, once the lid of a microplate is free of thestack, the presence of the recesses facilitates automated removal of thelid from the microplate. Pairs of opposite inwardly directed stopfingers 312, which may be otherwise similar to fingers 212, are insertedinto the recesses, 42 a and 42 b and 44 a and 44 b, so that at least aportion of the fingers are positioned directly above at least a portionof the microplate. A pair of opposite, inwardly-directed, liftingfingers 330 are then inserted into the recesses 50 a and 50 b so thatthey come immediately below the leading edges 52 a and 52 b,respectively.

As shown in FIG. 12, the lifting fingers 330 are raised to engage theleading edges 52 a and 52 b and raise the lid, with the stop fingers 312engaging the upper surface of the microplate so as to prevent movementof the microplate and permit separation of the lid from the microplate.

Although various processes have been described as performed relative tothe recesses 42 a and 42 b and 44 a and 44 b on the sides of the lid,such processes may also be performed relative to the recesses 46 a and46 b and 48 a and 48 b on the ends of the lid.

A number of embodiments of the present invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention. Forexample, although the illustrated recesses on a given side are formed inpairs on opposite sides of the associated center line (and particularlythe center of gravity), other configurations such as a bored recessesspanning the center line are similarly useful. Accordingly, otherembodiments are within the scope of the following claims.

Publications

All publications, including parent documents and scientific articles,referred to in this application are incorporated by reference in theirentirety for all purposes to the same extent as if each individualpublication were individually incorporated by reference.

All headings are for the convenience of the reader and should not beused to limit the meaning of the text that follows the heading, unlessso specified.

1-16. (Canceled).
 17. A lid comprising a rectangular surface comprisingan upper surface and a lower surface, said lower surface furthercomprising at least one flange, wherein said at least one flangecomprise at least one recessed area.
 18. The lid of claim 17, whereinsaid at least one flange is located substantially along the perimeteredge of said lower surface.
 19. The lid of claim 18, wherein said flangecomprises at least two recessed areas.
 20. The lid of claim 19, whereinsaid at least two recessed areas are arranged in a symmetrical pattern.21. The lid of claim 19, wherein said at least two recessed areas arearranged in a non-symmetrical pattern.
 22. The lid of claim 19, whereinsaid at least two recessed areas are disposed equally around the centerof gravity of said lid.
 23. The lid of claim 19, wherein said at leasttwo recessed areas are substantially circular or semicircular in shape.24. The lid of claim 19, wherein said at least two recessed areas aresubstantially triangular in shape.
 25. The lid of claim 19, wherein saidat least two recessed areas are substantially rectangular in shape. 26.The lid of claim 19, wherein said at least two recessed areas are notsubstantially the same shape.
 27. The lid of claim 18, furthercomprising a second at least one flange located on said upper surface.28. The lid of claim 27, wherein said second at least one flange furthercomprises at least one recessed area.
 29. A lid comprising a rectangularsurface and at least two sides attached to said rectangular surface, andeach said at least two sides, comprising at least one recessed area. 30.The lid of claim 29, wherein said at least one recessed area is adaptedto fit a device for engaging said lid for removal or placement on aplate.